1. Field of the Invention
This invention relates to novel anthracene compounds useful in the treatment of allergic, inflammatory conditions, tumor conditions and therapeutic compositions containing such compounds. The invention relates also to the therapeutic compositions effective at low dose with low irritancy. These anthracene compounds possess antitumor, antiproliferative, antipsoriatic, antiinflammatory, or antioxidant activity.
2. Description of the Prior Art
The discovery of the antitumor activity of 1,4-bis[(aminoalkyl)amino]anthracene-9, 10-diones such as ametantrone (1) and mitoxantrone (2) (FIG. 1) (Zee-Cheng, R. K. V. et al., J. Med. Chem., 21, 291-294 (1978); Zee-Cheng, R. K. V. et al., J. Pharm. Sci., 71, 708-709 (1982); Murdock, K. C. et al., J. Med. Chem., 22, 1024-1030 (1979)) has led to numerous physicochemical and pharmacological studies on the tumoricidal mechanisms of these chemotypes. Krapcho, A. P. et al., J. Med. Chem., 341, 2373-2380 (1991); Morier-Teissier, E. et al., J. Med. Chem., 36, 2084-2090 (1993). Additional references disclose 1,4- and 2,6-disubstituted or regioisomeric amidoanthracene-9,10-dione derivatives as inhibitors of human telomerase. Perry, P. J. et al., J. Med. Chem., 41, 3253-3260 (1998) and Perry, P. J. et al., J. Med. Chem., 41, 4873-4884 (1998).
Although the active mechanism of the antitumor activity of the anthracene-9,10-diones such as ametantrone (1) and mitoxantrone (2) is probably multimodal in nature, a number of studies have indicated that an intercalative interaction with DNA may be a major cellular event. Denny, W. A., Anti-Cancer Drug Design, 4, 241-263 (1989). Antitumor quinones represent the second largest class of clinically approved anticancer agents in the U.S.A., second only to the chloroethyl alkylating agents. They have been selected from the large number of naturally occurring quinones (Moore, H. W et al., Drugs Expl. Clin. Res., 12, 475-494, (1986)) and from synthetic quinones. Bruce, J. M. ed., Benzoquinones and Related Compounds, Vol. 3, Part 4, 1-306, (1974). The planar tricyclic system is known to intercalate into DNA base pairs and interfere in the transcription and replication processes of the cell. Johnson, R. K. et al., Cancer Treat. Rep., 63, 425-439 (1979); Lown, J. W. et al., Biochemisty, 24, 4028-4035 (1985). The DNA binding affinity (quantified as a binding affinity constant) and the dissociation rate constant for the DNA-ligand complex have been evaluated. Drug-DNA binding constants for ametantrone (1), mitoxantrone (2) and related congeners with calf thymus DNA show a large sensitivity to the position and number of the OH substitutions and the nature of the charged side chain. Denny, W A., Anti-Cancer Drug Design, 4, 241-263 (1989).
Normal human cells undergo a finite number of cell divisions and ultimately enter a nondividing state called replicative senescence. During successive rounds of cell division, the end-replication problem results in telomere shortening and ultimately senescence. As such, the loss of telomeric repeats after each round of cell division has been likened to a xe2x80x9cbiological clockxe2x80x9d limiting the proliferative life span of normal somatic cells. Harley, C. B. et al., Nature, 345, 458-460 (1990). Consequently, telomerase has been proposed as a potentially highly selective target for the development of a novel class of antiproliferative agents. However, in order for a therapeutic treatment to be effective, both the inflammatory and hyperproliferative aspects of the condition must be addressed. Substantial evidence suggests that free radicals and active oxygen species play a key role in both the therapeutic activity and side effects of anthracenone derivatives.
Anthraquinone-based compounds currently occupy a prominent position in cancer chemotherapy, with the naturally occurring aminoglycoside anthracycline doxorubicin and the aminoanthraquinone mitoxantrone both being in clinical use. These 1,5-dichloro-9(10H)-anthracenone compounds contain alkylacyl or arylacyl moieties at the C-9 position resulting in enhanced antiproliferative activity of the compounds. These blocked compounds may be further modified by introducing the phenolic form of the arylacyl or alkylacyl substituent.
As noted above, cancer is typically characterized by hyperproliferative component. There is thus a continuing need for effective compounds that address these aspects of cancer disease.
The present invention is directed to novel 9-substituted-1,5-dichloroanthracene compounds and salts thereof having therapeutic utility with respect to allergic or inflammatory or tumor conditions. In particular, many of the improved anthracene compounds provided for according to the invention are effective at low concentrations for the treatment of patients suffering from allergic or inflammatory or tumor conditions. Because these compounds may be administered at low concentrations, the undesirable allergic or inflammatory effects caused in whole or in part by free radicals or active oxygen species that are generated by anthracenone compounds are substantially eliminated.
Accordingly, in one embodiment of the invention, there is provided an anthracene compound according to Formula III below, said compound containing a substituent R, wherein R represents a branched or straight chain alkyl group having from 1 to 4 carbon atoms, said alkyl group being substituted with at least one substituent selected from carboxyl, carboxyl ester, hydroxy, phenyl, benzyl, substituted benzyl and substituted phenyl groups.
In a preferred embodiment of the invention, R represents a substituted phenyl group having at least one substituent selected from methyl, halogen and nitro groups. In another preferred embodiment, R represents a straight or branched chain alkyl group having 1 to 4 carbon atoms, which may contain a substituent selected from acyl and phenyl groups. Additionally, there are provided compounds which are functional analogs of the compounds of Formula III.
As aforementioned, therapeutic compositions of the invention are effective at dosages that substantially eliminate the adverse inflammatory or irritancy effects associated with the use of anthracenone and related compounds. Accordingly, there is provided a therapeutic composition comprising a therapeutically effective amount of at least one compound of the invention and a pharmaceutically acceptable carrier. These compounds of the invention have antiproliferative effects and antineoplastic effects.
Further additional representative and preferred aspects of the invention are described below according to the following detailed description of the invention.